The present invention relates in general to the production of interlaced or entangled multifilament yarns, and more particularly to methods for producing interlaced or entangled continuous multifilament synthetic yarn by impinging fluid streams or fluid jets on the yarn to impart entanglement thereto.
Heretofore, various methods have been used in the textile industry for producing a coherent yarn from a plurality of single-end, continuous, multifilament yarns by processes such as twisting, sizing, entangling, crimping, and the like. It is important to cohere together the filaments of multifilament yarns or to cohere yarns formed of two or more ends wound on a package, to improve the handling of the yarn in various textile operations and to keep the yarn together at all times during unwinding. It is a common occurrence that combinations of two or more yarn ends, when unwound, without having been twisted in advance, will cause problems which will result in machine stoppage and/or defective fabric with great frequency. Because of the difficulty in handling of yarn which has not been rendered properly coherent, it was customary for a long time to subject the yarn to the additional step of twisting each yarn, which served to compact and unify a yarn bundle resulting in a more cohesive structure which resists the pulling out of individual filaments. However, conventional true twisting was expensive and time consuming, and being a discontinuous operation, added disproportionately to the cost of the yarn. Also, the mechanics of true twisting and the additional handling required often resulted in yarn of lower quality.
More recently, processes have been adopted involving subjecting the yarn to high velocity fluid jets, generally created by compressed air, designed to have the capability of imparting entanglement or other different treatments to the yarn. Generally, such jets when used to produce entanglements, or what has been called "interlaced" yarn, have frequently been directed in a plane that is substantially normal to the direction in which the yarn advances, and in some cases have been directed along an axis inclined convergently to the yarn feed axis in the direction of yarn travel but intersecting the center of the yarn feed axis. It is of course, generally known that one single fluid jet design is incapable of producing all of the required yarn configurations and each fluid jet design is therefore limited to production, in general, of only one yarn type, such as a yarn type containing a large number of loops, or a yarn type providing slightly intermingled yarn filaments but producing no large or small loops.
An object of the present invention, therefore, is the provision of a novel method whereby two or more continuous synthetic multifilament yarns can be interlaced or entangled together continuously or at intervals with entanglement spacings positioned at random or fairly uniform distances as desired.
Another object of the present invention is the provision of a novel method for applying to filament yarns the force of suitable fluid jets, such as jets of compressed air or the like, in certain configurations and directions resulting in yarn interlacing providing a coherent yarn which will unwind from a yarn package without possibility of separation during further processing.
Another object of the present invention is the provision of a novel method for effecting intermittent or coherent entanglement to already bulked multifilament yarn by directing fluid jets of compressed air or the like against the yarn moving along a feed path and directed along jet axes which pass slightly to opposite sides of the center axis of the feed path so as not to intersect the center axis of the yarn feed path, to impart entanglement to the multifilament yarn permitting unwinding from a yarn package without separation of the yarn ends during further processing.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating preferred embodiments of the invention.